Midsummer Magic by Catherine Coulter (Magic Trilogy)

A clever, beautiful woman disguises herself as a mousy Scottish lass to keep the notoriously rakish Earl of Rothermere from marrying her, only to find she was chosen for that very reason. After the earl discards her, she sheds her dowdy facade to become London society's brightest star—rousing the ire and igniting the passions of her faithless husband.

Catherine Coulter is the author of the New York Times-bestselling FBI thrillers The Cove, The Maze, The Target, The Edge, Riptide, Hemlock Bay, Eleventh Hour, Blindside, Blowout, Point Blank, Double Take, TailSpin, KnockOut, and Whiplash. She lives in northern California.